The strategies discussed in "Increasing Adult Vaccination Rates: WhatWorks" were derived from the work of the Task Force on Community Preventive Services. The research involved a systematic review of studies concerned with the effectiveness of interventions designed to increase vaccination coverage levels in children, adolescents, and adults. Based on the research evidence, the Task Force provided recommendations on the use of the interventions. Key publications include:

Task Force on Community Preventive Services. Vaccine-preventable diseases: improving vaccination coverage in children, adolescents, and adults. A report on recommendations of the Task Force on Community Preventive Services. Morbidity and Mortality Weekly Report 1999;48(RR-8):1-15. http://www.cdc.gov/mmwr/preview/mmwrhtml/rr4808a1.htm

Note: The strategies presented in the "WhatWorks" training course are organized slightly differently to facilitate application in the clinical setting.

Interpreting the Studies: Dr. Paul Darden and his associates who have developed a self-instructional web-based training program "Teaching Immunization Delivery and Evaluation" (TIDE) provide a useful summary for interpreting the effectiveness findings:

"Unable to estimate" [insufficient evidence] means one of the following:

1. the studies were poor

2. not enough studies were done

3. the studies showed a small effect or no effect

4. there is a publication bias on negative studies (studies were done and the method was shown to be ineffective, but no journal was interested in publishing negative results, so the data is unavailable to us).

Note that criteria for judging the quality of the study are also listed. "For each of these criteria," the paper states, "reviewers were asked to determine if there was a threat to the validity of sufficient magnitude to diminish their confidence in the findings. Execution was characterized as good, fair or limited based on the total number of limitations noted."